1. Field of the Invention
The present invention relates to slit scan image capture systems for diagnostic evaluation of a patient's eyes. More specifically, the present invention is directed to slit scan image capture systems using rapid switching light sources, such as high luminescence light emitting diodes (HL-LEDs) or lasers.
2. Description of Related Art
In traditional slit scanning image capture systems, such as the Orbscan™, available from Bausch & Lomb Incorporated, the slit light source is focused white light from an incandescent source. These types of light sources typically have a relatively long period of time required to power-up to a full power state and to deactivate or power-down to a zero power state. This period of time is typically in the hundreds of milliseconds.
These long power-up and power-down time periods require the slit lamps to be fully powered-up during the duration of an eye exam on a patient. For example, the Orbscan™ is a moving slit system which requires the slit to be moved incrementally across the eye from time to time and at other times, the slit is to remain stationary for an image to be captured by the system.
As a motor causes a slit source to move, thereby causing a slit illumination to be moved across the eye, this movement causes a smear of light across the eye. This smear makes the image useless for analysis, and is therefore discarded. This discarded image reflects an amount of time that the patient is required to hold their eye still, but yet no data is acquired. This time period therefore represents an opportunity for increased efficiency in obtaining slit images.
Reducing the amount of exam time for obtaining eye images is important in order to reduce the amount of time that a patient must hold their eye steady, which can lead to lower quality of data acquired. The longer a patient must hold his eye steady, the more his eye may dry out which also reduces image quality, as well as leads to discomfort and natural eye movement.
Another approach to solving this problem could involve something similar to a motion picture projector. This solution would utilize a mechanical shutter which would shield the light from the lamp, while the slit source is moving. This then allows a second lamp to expose a slit image onto the eye for data capture while the first motor is moving the first slit source. However, accomplishing this would require a very rapid shutter system, which would need to be electronically synchronized to the analog video camera. This approach would be costly and complicated. In addition, the use of mechanical parts would lead to failures due to worn mechanical parts.
Therefore, it would be desirable to provide a solution where the amount of exam time is greatly reduced while providing for a relatively simple and inexpensive means for acquiring the necessary images.